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| author | H. Peter Anvin <hpa@zytor.com> | 2012-06-17 08:47:37 +0400 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2012-06-17 21:51:01 +0400 |
| commit | 650513979a437c32d7a0a84f0ed952a55bbb5583 (patch) | |
| tree | b831bcbfdfce6abb31573e67669272f368626b5b /arch/x86/realmode/rm | |
| parent | cfaf025112d3856637ff34a767ef785ef5cf2ca9 (diff) | |
| download | linux-650513979a437c32d7a0a84f0ed952a55bbb5583.tar.xz | |
x86-64, reboot: Allow reboot=bios and reboot-cpu override on x86-64
With the revamped realmode trampoline code, it is trivial to extend
support for reboot=bios to x86-64. Furthermore, while we are at it,
remove the restriction that only we can only override the reboot CPU
on 32 bits.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-jopx7y6g6dbcx4tpal8q0jlr@git.kernel.org
Diffstat (limited to 'arch/x86/realmode/rm')
| -rw-r--r-- | arch/x86/realmode/rm/Makefile | 2 | ||||
| -rw-r--r-- | arch/x86/realmode/rm/header.S | 4 | ||||
| -rw-r--r-- | arch/x86/realmode/rm/reboot.S (renamed from arch/x86/realmode/rm/reboot_32.S) | 26 |
3 files changed, 27 insertions, 5 deletions
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index 5b84a2d30888..b2d534cab25f 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -22,7 +22,7 @@ wakeup-objs += video-bios.o realmode-y += header.o realmode-y += trampoline_$(BITS).o realmode-y += stack.o -realmode-$(CONFIG_X86_32) += reboot_32.o +realmode-y += reboot.o realmode-$(CONFIG_ACPI_SLEEP) += $(wakeup-objs) targets += $(realmode-y) diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S index fadf48378ada..a28221d94e69 100644 --- a/arch/x86/realmode/rm/header.S +++ b/arch/x86/realmode/rm/header.S @@ -6,6 +6,7 @@ #include <linux/linkage.h> #include <asm/page_types.h> +#include <asm/segment.h> #include "realmode.h" @@ -28,8 +29,9 @@ GLOBAL(real_mode_header) .long pa_wakeup_header #endif /* APM/BIOS reboot */ -#ifdef CONFIG_X86_32 .long pa_machine_real_restart_asm +#ifdef CONFIG_X86_64 + .long __KERNEL32_CS #endif END(real_mode_header) diff --git a/arch/x86/realmode/rm/reboot_32.S b/arch/x86/realmode/rm/reboot.S index 114044876b3d..6bf8feac5557 100644 --- a/arch/x86/realmode/rm/reboot_32.S +++ b/arch/x86/realmode/rm/reboot.S @@ -2,6 +2,8 @@ #include <linux/init.h> #include <asm/segment.h> #include <asm/page_types.h> +#include <asm/processor-flags.h> +#include <asm/msr-index.h> #include "realmode.h" /* @@ -12,13 +14,31 @@ * doesn't work with at least one type of 486 motherboard. It is easy * to stop this code working; hence the copious comments. * - * This code is called with the restart type (0 = BIOS, 1 = APM) in %eax. + * This code is called with the restart type (0 = BIOS, 1 = APM) in + * the primary argument register (%eax for 32 bit, %edi for 64 bit). */ .section ".text32", "ax" .code32 - - .balign 16 ENTRY(machine_real_restart_asm) + +#ifdef CONFIG_X86_64 + + /* Disable paging to drop us out of long mode */ + movl %cr0, %eax + andl $~X86_CR0_PG, %eax + movl %eax, %cr0 + jmp 1f /* "A branch" may be needed here, assume near is OK */ + +1: + xorl %eax, %eax + xorl %edx, %edx + movl $MSR_EFER, %ecx + wrmsr + + movl %edi, %eax + +#endif /* CONFIG_X86_64 */ + /* Set up the IDT for real mode. */ lidtl pa_machine_real_restart_idt |